Because it wasn't finished, the only work that was done was on the aerodynamics and automatic control systems. Life support, re-entry and so on are all still undeveloped.

Oh, and to "sell" it, (which would be against NASA policy) would require them to charge a similar amount of money as they put into developing it...

Which is in the range of several billion dollars.

I'm sure groups will use pre-existing launch vehicles, but manned capsules or spaceplanes are a rare thing, and the only one ever developed which was not ridiculously expensive was SpaceShipOne. It is quite literally, a thousand times cheaper than anything that has gone before.

IMO the only upper stage design worth envisioning for a private orbital launch system is a lifting body design, similar to HL-42 or the X38.
You might be right about NASA not wanting to sell the plans, and that they might be incomplete at best. But at least the information that has been released through published papers provides a good start for a company to design their own orbiter.

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IMO the only upper stage design worth envisioning for a private orbital launch system is a lifting body design, similar to HL-42 or the X38.

What makes a lifting body design so superior to other designs? NASA got to the moon and back using standard capsule designs, which cost a fraction to design, validate and build. Using carefully calculated re-entry they can still re-enter fairly accurately (to within 50 miles or so), and using a parafoil instead of a circular parachute could probably let you land on a designated landing strip.

Also a standard spaceplane is also easier to design and build, and can be landed just as accurately as the lifting body design.

The benefits of the lifting body design, as far as I know, were it's carefree landing (it was autonomous), and an increased compactness. Apart from a fact that private firms don't have the money to seperately develop the software needed to control such a vehicle, lifting body designs are inherantly unstable and need a lot of extra aerodynamic work to help them work.

Basically, if you're not NASA and willing to spend big bucks, it seems like a bit of an overkill to me. We're not looking for the most technically elegant solution to the problems of spaceflight, we're looking for the cheapest.

[The benefits of the lifting body design, as far as I know, were it's carefree landing (it was autonomous), and an increased compactness. Apart from a fact that private firms don't have the money to seperately develop the software needed to control such a vehicle, lifting body designs are inherantly unstable and need a lot of extra aerodynamic work to help them work.

all i can say is armadillo. they've already got a good start on software for automating a vehicle like that, all their programming is done in-house, and- call me a fan as you will- but JC really is a programming god. if it's possible with current hardware he can make it happen.

I'm pretty sure lifting bodies get "lift" from the shape of their bodies rather than just their wings. Besides being expensive, Lifting Bodies can be hard to control, thats one reason why we don't use them in everyday airplane design. Current airplane design uses a tube for the cabin space, not much lift generated there.

capsules cannot splashdown on conventional runways and anywhere near civilization and thus require an extensive recovery system which obvioulsy caosts a lot of money.
spaceplanes have wings and wings are not good during re-entry;the Columbia tragedy is the best example.
I think all future spacecraft that must fly theough the atmosphere will be lifting bodies.

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Sure we are looking for the cheapest, but also the most reliable, and easy to build. These lifting body designs are not exactly hard to build, and the fact that things like the space shuttle cost billions each is proposterous. Who actually sets prices on the parts? NASA spent too much on its little inventions because they could. The government through billions at them to build. Nowadays to build something like the space shuttle would be very expensive...but why? If you can build something like spaceshipone with millions, then why does it cost billions to build something that is out of date? Think of the market, the companies producing parts have been charging ridiculous prices because NASA would pay them. The market now, since private companies are getting into it, should have to go down in price anyway. And since most companies are making there own designs, it doesnt cost billions to create something, more like 400 bucks for a crazy CAD program. Its just amusing as to how NASA didn't do much with Billions a year in budget...

Concerning the wings as discussed in this thread at least a little bit - might there be a way to provide wings for spacecrafts that can be shifted, rolled up, pulled into the craft and out again later or something like this?

Then the vehicle could start having the wings shifted or folded (etc.) out and the shift or fold (...) them in in regoions where they are useless. It should keep then shifted or folded in during reentry and shiftbthem out later again in regions where they provide use.

May that be a raw idea for a technology prize to be offered by WTN & XPRIZE Foundation?

Ok, a couple of points. Firstly Ekkehard, that is a good idea except that the wings are a part of the design that helps slow down re-entry, as well as distribute the heat (I mentioned this in another thread to you), although yes with sufficiently advanced heat shielding it could help.

As for lifting body designs, to all you who said it would be "easy" to design such a thing. Well, unless you can state a decent number of aerodynamic engineering credentials, I do wonder how you came to that conclusion. While I do admittedly do physics, not aerodynamics, from people who I have talked to who work in the area, it is very hard to get a stable lifting body design, as they are particularly prone to oscillations and stalls. Also, it would take a lot more research and design to come up with a working system.

Consider the X-Prize. Of all the teams who have got somewhere yet, how many actually involved advanced custom aerodynamics (ie, designing an aeroplane) into their entry? One. Yes, they happened to win, but they were also the most technically advanced and capable group out there. Personally, I think even Rutan would struggle to design a lifting body design. Unlike normal aeroplanes, there are not really any precedents for a passenger capable design, and all prototypes that have been designed thus far have serious flaws. They also tend to be a lot heavier than normal body designs, since in a normal aeroplane design both the wing and tube are designed around a single aim (creating lift and storing people respectively) each, so not much space is wasted. Trying to amalgemate the two creates quite a lot of wasted space, as well as reducing the actual control over the craft.

Then the vehicle could start having the wings shifted or folded (etc.) out and the shift or fold (...) them in in regoions where they are useless. It should keep then shifted or folded in during reentry and shiftbthem out later again in regions where they provide use.

AFAIK, these mechanisms are generally pretty complex and heavy. I think this would negate most of the advantages you wanted to gain.

Sev wrote:

They also tend to be a lot heavier than normal body designs, since in a normal aeroplane design both the wing and tube are designed around a single aim (creating lift and storing people respectively) each, so not much space is wasted. Trying to amalgemate the two creates quite a lot of wasted space, as well as reducing the actual control over the craft.

I'm not sure I follow your reasoning here. Why would you waste space if you combine the functions of generating lift and storing people? I would say you'd have rather the reverse effect. It does not sound efficient to me to use a huge tube to store people only for doing that, if you could also use it for generating lift (and vise versa for the wings). Could you eleborate on this?

As Sev listed in his tabel in "Possible Craft" under "Bigelow's Americas' Space Prize" The Falcon V will lift 476 kg per m$ and has launch costs of 12m $. The Shuttle has launch costs of 1,2 billion $ - lifting 60 t to orbit means 50 kg per m$.

I don't know this moment the capacity of the Falcon V in kg but he has to be launched a hundred times until the launch costs of the Shuttle are summed up.

What's left is that the Falcon perhaps cannot return cargo - but as I remarked much earlier: Why something return to earth's surface if could still do good use in space? If SpaceX, Interorbital Systems, Scaled/Mojave or another participant of America's Space Prize succeeds repairs in orbit are possible at much less costs than by using the Shuttle.